1. Field of the Invention
The present invention relates to chewing gum compositions and especially chewing gum compositions incorporating in combination at least one non-toxic source of acid and calcined kaolin particles capable of cleaning and imparting a high degree of polish to the teeth and of reducing the rate of dental plaque formation.
2. Description of the Prior Art
Dental research has developed substantial evidence that dental plaque is the predominant etiological factor responsible for both periodontal disease and dental caries. Dental caries is the localized, progressive decay of the teeth. It results from tooth demineralization brought about by acids formed when bacteria in dental plaque ferment carbohydrate foods present in the mouth.
With the discovery of fluorides, advances have been made in the reduction of dental caries. However, this progress has been somewhat offset for a variety of reasons, among them the increased intake of sugar-containing processed foods and snacks, as well as poor oral hygiene habits and attitudes. In fact dental caries, which afflicts more than 95% of Americans by the time they become adults, is the most prevalent disease in the United States with the exception of the common cold.
After the age of 35, the main cause of tooth loss is due to periodontal disease. The most important single factor contributing to periodontal disease is the accumulation of plaque and dental calculus (e.g., salivary tartar) on the teeth. These deposits result in tissue inflammation of the surrounding gingiva, and, as the condition increases in severity, the supporting bone is also affected. These reactions lead to the destruction of the supporting structures and the subsequent mass loss of teeth which are usually free of decay.
Although brushing the teeth with a toothbrush and dentifrice is a widely recognized technique for maintaining dental health, the average American brushes only about once a day for approximately one minute. Therefore, a great need exists for finding additional methods for improving daily oral hygiene. Chewing gum has over the years been advocated as a possible excellent adjunct for cleaning the teeth because people find the chewing of gum very pleasurable and chew gum for much longer periods of time than they brush their teeth. Chewing gum is especially advantageous for use in circumstances where toothbrushing is not possible or convenient, such as after lunch, while traveling, or while working. However, while mastication of conventional chewing gum is known to be capable of reducing the amount of debris on and between the teeth, gum chewing has been shown to be incapable of removing dental plaque, calculus or stain from the teeth without added therapeutic agents. And, while chewing gums have often been proposed as vehicles for the administration of dental therapeutic agents such as fluorides, phosphates, enzymes, and other materials, none of these systems has been made commercially available because of insufficient supporting data or toxicological problems.
The concept of high enamel polish is recognized to be critical to good oral hygiene because smooth, polished tooth surfaces have fewer nidi or sites to which oral bacteria adhere than do unpolished, rough enamel surfaces. The primary reason dental caries and periodontal disease develop is that such bacteria adhere to and grow on enamel surfaces. By physically polishing the dental enamel, the potential for bacteria colonization on the teeth is reduced, less bacterial plaque is formed, and, consequently, dental caries and periodontal disease are inhibited. The high polished concept, thus, would offer a significant approach to the prevention of dental plaque and exogenous stain if a proper vehicle for its application could be developed.
Available dentifrice abrasives have, when employed in dentifrices, exhibited relatively unsatisfactory enamel polishing qualities and consequently have not been wholly effective in preventing the re-accumulation of materia alba, oral debris, plaque, pellicle, stains, and dental calculus.
In particular, while conventional cleaning and polishing agents used with a toothbrush are capable, to varying degrees, of removing materia alba, food particles, exogenous stains, and other tooth surface pigmentations when utilized in ordinary daily brushings, they are generally ineffective in removing the more resistant forms of enamel pigments and usually lack the polishing characteristics necessary to produce a smooth surface that is resistant to plaque and dental calculus reformation.
In fact, conventional agents often are quite abrasive to the tooth surfaces and tend to erode the tooth enamel and the surrounding soft dentin areas. This abrasion leaves a rough tooth surface that actually facilitates the re-accumulation of pellicle (the precursor to dental stains) and plaque (the precursor to dental caries, periodontal disease and calculus). Furthermore, these conventional dental abrasives leave the teeth aesthetically less desirable than would more effective polishing agents.
A chewing gum capable of cleaning and polishing the teeth is disclosed in U.S. Pat. No. 3,590,120 granted June 29, 1971 to the assignee of this application. That patent describes the addition to a chewing gum during its formulation of zirconium silicate (ZrSiO.sub.4) of highly specific particle size and surface configuration. While chewing gums produced in accordance with U.S. Pat. No. 3,590,120 have polished the teeth with good success, because zirconium silicate is a hard mineral, the teeth have also been scratched slightly. In addition, zirconium silicate is slightly radioactive, a factor which has also limited application of the techniques of the U.S. Pat. No. 3,590,120. U.S. Pat. No. 3,590,120 also suggests that zirconium silicate may be combined with other abrasives such as kaolinite but does not recognize that kaolinite must be calcined in order to impart high polish to the teeth.
The use of calcined kaolin as a dentifrice abrasive in combination with fluoride is known from U.S. Pat. No. 4,122,163, also assigned to applicants' assignee. That patent is concerned with the application of highly purified calcined kaolin in dentifrices but does not recognize the existence of any other potential applications in the oral hygiene field.
Accordingly, it is a primary object of the present invention to provide a chewing gum capable of removing dental plaque and of imparting a high degree of polish to the teeth.
Another object is to provide a chewing gum capable of cleaning and polishing the teeth without unduly abrading or scratching the enamel surface.
A still further object is the provision of a new dental cleaning and polishing system which may be incorporated into chewing gums in order to permit successful application of the high polish oral hygiene concept.
A still further object is to provide methods of polishing the teeth and inhibiting the formation of dental plaque by using chewing gum compositions of the character described.